body{
    /* 插入背景图片 */
    background-image: url('star.jpg');
    background-repeat: no-repeat;
    overflow: hidden;
    /* 剪切 */
    background-size: cover;
    /* 背景图垂直、水平均居中 */
    background-position: center;
    /* 当内容高度大于图片高度时，背景图像的位置相对于viewport固定 */
    background-attachment: fixed;
    /* 让背景图片放大到合适大小 */
    background-size: cover;   
} 
.header{
    color:rgb(116, 145, 170);
    text-align: center;
    padding: 1cap;
    
}
.container{
    margin-left: 500px;
    margin-top: 150px;
    width: 380px;
    height: 200px;
    margin: 7% auto;  
    background-color: rgba(0,0,0,0.7);
    box-shadow: 0 0 17px;
}
form .pwd{
    width: 55%;
    color:azure;
    background-color:rgb(55, 55, 161);
    margin-top: 10px;
}
.down1 {
    color: white;
    font-size: 11px;
    margin: 550px 100px 10px 550px;
}

.down2 {
    color: white;
    font-size: 11px;
    margin: 0px 0 0 650px;
}